1. Field of the Invention
The present invention relates to a mobile terminal device installed with a fingerprint sensor, and particularly to battery saving technology for a mobile terminal device.
2. Description of Related Art
In recent years, personal verification has become increasingly important in a variety of applications starting with electronic commercial transactions utilizing a mobile terminal device. Amongst means available for verifying individuals, fingerprint verification is one means with a high possibility of practical implementation in a mobile terminal device due to considerations of the cost of sensors and size.
Among existing fingerprint verification technology there are systems with a personal computer installed utilizing a login function and those used instead of a door key in the entranceway to an apartment building.
The existing technology is confronted by the following problems however. Firstly, a fingerprint sensor of the prior art still consumes considerable power and a mobile terminal device driven by a battery, that has only limited power storage capacity, can only be used for a short time.
Secondly, most fingerprint sensors of the prior art have a sensor cover because they are relatively susceptible to static electricity and do not have a strong surface, but the sensor power supply does not work synchronously with the opening and closing of the sensor cover so that power is supplied even when the sensor cover is closed and electricity consumption continues.
In JP H04-4352 U, it is described technology wherein power supply for a sensor cover and fingerprint input part as well as a fingerprint verification part is synchronized and power supply comes on only when the sensor cover is open, however a problem remains in that when the fingerprint sensor is not used while the sensor cover is open electricity consumption continues Further, basic fingerprint registration and verification methodology for that invention is not described and operations when there is a fingerprint image read-in command before the opening of the sensor cover, that is, prior to commencement of power supply, are not clear.
The present invention was developed against this background for the objective of providing a mobile terminal device wherein the opening and closing of a sensor cover works in synchronicity with on/off control of power supply for a fingerprint sensor and wherein even when the sensor cover is open, wasteful electricity consumption through power supply continuing if the fingerprint sensor is not used within a specified period of time is prevented. A further object of the present invention is to provide a mobile terminal device wherein, with the sensor cover open, even if power supply to the fingerprint sensor is off, an image can be read-in to the fingerprint sensor when a fingerprint image read-in command executes. Another object of the present invention is to provide a mobile terminal device wherein when a fingerprint image read-in command executes while the sensor cover is closed, that command is invalidated thereby avoiding consumption of battery power.
In the present invention the opening and closing of a sensor cover works in synchronicity with power supply for a fingerprint sensor being turned on or off, and even when the sensor cover is open if the fingerprint sensor is not used wasteful consumption of power is prevented.
That is to say, the present invention operates such that time elapsed from the time when the sensor cover is opened, that is, the time from which power supply to the fingerprint sensor is turned on, is counted, and when there is no fingerprint image read-in command within a specified period of time, power supply to the fingerprint sensor is turned off, so that saving of the battery is achieved because if the fingerprint sensor is not used within a predetermined period of time power supply to the fingerprint sensor is turned off automatically.
Further, the present invention operates such that even if power supply to the fingerprint sensor is turned off, when a fingerprint image read-in command is generated power supply to the fingerprint sensor is turned on enabling read-in of a fingerprint image to commence. That is to say, even while the fingerprint sensor power supply is off monitoring is performed to ascertain the existence or otherwise of a fingerprint image read-in command and the fingerprint sensor power supply can be turned on if that command is present.
Again, the present invention operates such that when a fingerprint image read-in command is generated while the sensor cover is closed, that command is invalidated thereby preventing battery power consumption from the fingerprint sensor power supply going on through an operational error.
That is to say, the present invention is a mobile wireless terminal device comprising a fingerprint sensor for reading in a fingerprint image and a sensor cover covering the fingerprint sensor wherein the sensor cover is manually opened or closed over the fingerprint sensor.
The present invention is characterized by comprising; a detection means for detecting whether or not the sensor cover is open or closed; a first control means that operates in accordance with the result detected by the detection means and turns on power supply to the fingerprint sensor when the sensor cover is in an open condition and turns off power supply to the fingerprint sensor when the sensor cover is in a closed condition; a counting means for counting time elapsed from the point in time at which the sensor cover is detected as being open; a fingerprint image read-in command generating means for generating a fingerprint image read-in command in response to manual operation; a monitoring means for monitoring whether or not that fingerprint image read-in command is generated; a reset/restart means that resets and restarts the count during the counting process if a fingerprint image read-in command is generated while the counting is being performed; and a second control means that turns power supply to the fingerprint sensor off when there is no fingerprint image read-in command within a specified period of time from the commencement of counting by the counting means, even when the sensor cover is in an open condition.
Accordingly, in the present invention the opening and closing of the sensor cover works in synchronicity with power supply for the fingerprint sensor being turned on or off and even when the sensor cover is open, if the fingerprint sensor is not used beyond a specified time, power supply to the fingerprint sensor is turned off thereby avoiding wasteful power consumption.
It is preferable for the present invention to comprise a third control means that turns power supply to the fingerprint sensor on when a fingerprint image read-in command is generated by the fingerprint image read-in command generating means even though power to the fingerprint sensor is off moreover the sensor cover is in an open condition as detected by the second control means.
This means that an image can be read-in to the fingerprint sensor when a fingerprint image read-in command is generated even though the fingerprint sensor power supply is off while the sensor cover is in an open condition.
It is preferable for the present invention to comprise a means to invalidate a fingerprint image read-in command when a fingerprint image read-in command is issued by the fingerprint image read-in command generating means at times when the result detected by the detection means indicates that the sensor cover is closed.
Accordingly, the present invention operates such that when a fingerprint image read-in command executes while the sensor cover is closed, that command is invalidated thereby preventing battery power consumption through an operational error.